Microsoft is investigating whether a leak from its early alert system for cybersecurity companies allowed Chinese hackers to exploit flaws in its SharePoint service before they were patched, Bloomberg News reported on Friday.

Microsoft said that a hacking group it's tracking as Storm-2603 is exploiting critical vulnerabilities in the company's SharePoint platform to deploy ransomware.

Recent attacks targeting Microsoft SharePoint have escalated, with threat actors now deploying ransomware on vulnerable systems, according to Microsoft.

Several entities in South Africa have been compromised by hackers who exploited a security vulnerability in Microsoft Corp.’s SharePoint servers, according to Eye Security, the cybersecurity company that identified an early wave of attacks last week.